I haven't seen any scans of AstroDon "E"
series filters on the web. Thomas Baader of Baader Planetarium sent me these
scans August 20, 2007 in response to a question I had asked him about NIR leakage
reports made Don Goldman involving Baader's Halpha Narrowband filter.

As I understand Mr Baader only had the "E"
series LRGB filters from AstroDon available for measurement at this time, but he
did scan these filters and provided me these scans including one of his 7nm
Halpha filter for reference. I asked Mr. Baader how these scans were made and he
replied they were measured using a Perkin Elmer Lambda 900 Precision
Spectrophotometer with
a 90 degree incidence angle. By contrast Don Goldman said he measured the
results he reports using a flashlight shone off the ceiling in a dimly lit
office. Some of Goldman's comments are reproduced below in accordance with
17USC section 107 "Fair Use"

"To test NIR leakage, I used
an Apogee Alta U16M CCD with a Kodak KAF16803 large format CCD operated
at -20C in my dimly lit office with a standard
flashlight directed at the ceiling. The camera was
pointed up. A 2" nose piece was secured into the camera holding a
standard 48 mm Astrodon Schuler photometric (Bessell, Johnson-Cousins) IR
filter made with 3 mm thick piece of Schott RG9 glass and 1 mm of KG4 glass.
This filter is used to compare the IR leakage of the two H-a filters,
because it blocks the filter's bandpass and all shorter wavelengths.
It's scan (Is) is shown below:"

So in the spirit of seeking the truth no
matter where it carries us, here are the scans I was given.

It seems curious that Mr. Goldman raised
issues about NIR leakage in Baader's 7nm Halpha filter when his LRGB filters
clearly exhibit stronger NIR leakage than the Baader Halpha. Note
that the Red AstroDon filter appears to begin to show leakage as the scan
stopped at 1200nm.